Ventilation device for pouch-type secondary battery and battery module including the same

ABSTRACT

A ventilation device for a secondary battery includes a frame including a first frame and a second frame, and a connector connecting the first frame and the second frame to each other and including a slit portion formed therein. Each of the first frame and the second frame has a facing surface that faces each other, and at least one of the first frame and the second frame includes a ventilation guiding portion recessed from the facing surface, and a ventilation control portion is formed to provide a space between the first frame and the second frame and to be connected to the ventilation guiding portion.

PRIORITY CLAIM AND CROSS-REFERENCE TO RELATED APPLICATION

This patent document claims the priority and benefits of Korean PatentApplications No. 10-2021-0079217 filed at the Korean IntellectualProperty Office (KIPO) on Jun. 18, 2021 and No. 10-2022-0027237 filed atthe KIPO on Mar. 3, 2022. The entire contents of each application areincorporated by reference in this document in their entirety.

TECHNICAL FIELD

This patent document relates to a ventilation device for a pouch-typesecondary battery and a battery module including the same.

BACKGROUND

The rapid growth of electric vehicles and portable devices, such ascamcorders, mobile phones, and laptop computers, has brought increasingdemands for secondary batteries, which can be charged and dischargedrepeatedly.

Examples of the secondary batteries include lithium secondary batteries,nickel-cadmium batteries, and nickel-hydrogen batteries. The lithiumsecondary batteries are now widely used due to certain advantages overother types of batteries, including, e.g., high operational voltage andenergy density per unit weight, a high charging rate, a compactdimension, etc.

A lithium secondary battery may include an electrode assembly includinga cathode, an anode and a separation layer (separator), and anelectrolyte immersing the electrode assembly. The lithium secondarybattery may further include an outer case having, e.g., a pouch shapefor accommodating the electrode assembly and the electrolyte.

When a pouch-type lithium secondary battery is exposed to a harshenvironment, a gas may be continuously generated inside of the battery,increasing an internal pressure of the pouch. If the internal pressureis increased beyond a tolerable critical value, a sealing portion at theweakest portion of the pouch may be damaged to cause a ventilation. Theventilation may occur randomly in the pouch, and the location where theventilation occurs may not be easily predicted.

In order to address such issues, some lithium secondary battery designsinclude a lamination film that is welded at a sealing portion of apouch-type battery to induce a directional venting of a gas generated inthe pouch. However, sufficient venting inducing effects and battery cellstability may not be provided.

SUMMARY

This patent document discloses technical features and examples for aventilation device for a pouch-type secondary battery having improvedventilation control properties.

According to an aspect of the disclosed technology, there is provided abattery module having improved ventilation control properties.

According to some embodiments of the disclosed technology, a ventilationdevice for a pouch-type secondary battery includes a frame comprising afirst frame and a second frame, and a connector connecting the firstframe and the second frame to each other and having a slit portionformed therein. Each of the first frame and the second frame has afacing surface to each other, and at least one of the first frame andthe second frame includes a ventilation guiding portion recessed fromthe facing surface. A ventilation control portion is formed as a spacebetween the first frame and the second frame to be connected to theventilation guiding portion.

In some embodiments, the connector may extend from a rear surface of thefirst frame to be connected to a rear surface of the second frame, thefirst frame may have a first frame facing surface facing the secondframe and a first ventilation guiding surface recessed from the firstframe facing surface, the second frame may haves a second frame facingsurface facing the first frame and a second ventilation guiding surfacerecessed from the second frame facing surface, and the ventilationguiding portion may be formed between the first ventilation guidingsurface and the second ventilation guiding surface.

In some embodiments, the slit portion may extend between the first frameand the second frame, and the ventilation guiding portion may beadjacent to one end of the slit portion and may be opened to an outsideof the frame.

In some embodiments, the ventilation guiding portion may include aventing groove.

In some embodiments, the ventilation guiding portion may include aventing hole.

In some embodiments, an inner shape of the venting hole may include atleast one of a cylindrical shape, a semi-cylindrical shape, a funnelshape and a polygonal pillar shape.

In some embodiments, wherein an average diameter of each of thecylindrical shape, the semi-cylindrical shape and the funnel shape maybe from 1 mm Φ to 500 mm Φ.

In some embodiments, a cap may be fitted to the ventilation guidingportion.

In some embodiments, the cap may include a material having a ductilitygreater than that of a material of the frame.

In some embodiments, the slit portion may have a sub-venting hole havingthe same shape as that of the ventilation guiding portion at a positioncorresponding to the ventilation guiding portion.

In some embodiments, an interval between the first frame and the secondframe may be from 0.1 nm to 10 mm.

According to some embodiments of the disclosed technology, a batterymodule includes a plurality of battery cells stacked on each other, eachof the plurality of battery cells including an electrode lead, and a busbar assembly coupled to an end from which the electrode leads of theplurality of battery cells are drawn out to connect the plurality ofbattery cells to each other. The bus bar assembly includes a main frameincluding a slit portion from which the electrode leads of the pluralityof battery cells are drawn out, a bus bar mounted on an outer surface ofthe main frame to electrically connect the electrode leads drawn outthrough the slit portion to each other, and a plurality of inner framesspaced apart from each other on an inner surface of the main frame toguide the electrode lead to the slit portion. The plurality of innerframes includes a first inner frame and a second inner frame neighboringeach other, and the first inner frame includes a ventilation guidingportion recessed from a surface facing the second inner frame, and aventilation control portion is formed as a space between the first innerframe and the second inner frame to be connected to the ventilationguiding portion.

In some embodiments, the first inner frame may have a first inner framefacing surface facing the second inner frame, and a first innerventilation guiding surface recessed from the first inner frame facingsurface. The second inner frame may have a second inner frame facingsurface facing the first inner frame, and a second inner ventilationguiding surface recessed from the second inner frame facing surface. Theventilation guiding portion may be formed between the first innerventilation guiding surface and the second inner ventilation guidingsurface.

In some embodiments, the plurality of battery cells may each include anelectrode assembly and a pouch for accommodating the electrode assembly.The pouch may include a sealing portion formed at an outside theelectrode assembly, and the electrode lead and the sealing portion maybe at least partially located in the ventilation control portion.

In some embodiments, at least a portion of the sealing portion may be incontact with at least a portion of the first inner frame facing surfaceand the second inner frame facing surface in the ventilation controlportion.

In some embodiments, the sealing portion may include a side sealingportion sealing an end from which the electrode lead is drawn out, and amain sealing portion sealing a side from which the electrode lead is notdrawn out. The main sealing portion may have a folding portion in whichthe pouch is folded at an edge thereof. A contact area of the sidesealing portion with the first inner frame facing surface and the secondinner frame facing surface is from 200 mm2 to 20,000 mm².

In some embodiments, the ventilation guiding portion may be adjacent toone end of the slit portion and may be opened to an outside of at leastone inner frame among the plurality of inner frames.

In some embodiments, an inner shape of the ventilation guiding portionmay include at least one of a cylindrical shape, a semi-cylindricalshape, a funnel shape and a polygonal pillar shape.

In some embodiments, a cap may be fitted to the ventilation guidingportion.

In some embodiments, the cap may include a material having greaterductility than that of the plurality of inner frames.

In some embodiments, an interval between the plurality of inner framesmay be from 0.1 mm to 10 mm.

In some embodiments, the slit portion may have a sub-venting hole havingthe same shape as that of the ventilation guiding portion at a positioncorresponding to the ventilation guiding portion.

In a ventilation device for a pouch-type secondary battery according toembodiments of the disclosed technology, a ventilation caused by a gasgenerated at an inside of the pouch may be delayed. The gas may beinduced in a specific direction to be discharged even when a ventilationoccurs, so that damage or explosion of a battery cell may be prevented.

In some embodiments, a pouch expansion may be suppressed by aventilation control portion of the ventilation device to prevent ordelay the vent.

In some embodiments, the ventilation device for a pouch-type secondarybattery may guide a direction of the gas to a ventilation guidingportion, so that a region or a time of the ventilation generation may bepredicted. Further, an additional device (e.g., a venting unit) may beomitted so that productivity of the secondary battery or a batterymodule may be enhanced.

In a battery module including the ventilation device for a pouch-typesecondary battery according to exemplary embodiments, a ventilation maybe controlled to maintain stability even when a pressure at an inside ofa battery pouch may be increased beyond an appropriate level.Accordingly, stability of the battery cell may be achieved anddeterioration of a battery cell performance may be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view illustrating a ventilation devicefor a pouch-type secondary battery in accordance with exemplaryembodiments.

FIGS. 2A to 2D are schematic perspective views illustrating ventilationdevices for a pouch-type secondary battery in accordance with someexemplary embodiments.

FIGS. 3A to 3B are schematic perspective views illustrating ventilationdevices for a pouch-type secondary battery in accordance with someexemplary embodiments.

FIG. 4 is a schematic perspective view illustrating a ventilation devicefor a pouch-type secondary battery in accordance with some exemplaryembodiments.

FIGS. 5A and 5B are schematic perspective views illustrating ventilationdevices for a pouch-type secondary battery in accordance with soreexemplary embodiments.

FIG. 6 is a schematic top plan view of a battery cell in accordance withexemplary embodiments.

FIG. 7 is a schematic perspective view illustrating a battery cell unitin accordance with exemplary embodiments

FIG. 8 is a schematic diagram for describing an operation mechanism of abattery cell unit in accordance with exemplary embodiments.

FIG. 9 is a schematic perspective view illustrating a battery module inaccordance with exemplary embodiments.

FIGS. 10 and 11 are schematic cross-sectional views illustrating batterymodules in accordance with exemplary embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

According to exemplary embodiments of the disclosed technology, aventilation device for a pouch-type secondary battery capable ofreducing or delaying a gas generated in a battery cell is provided.According to exemplary embodiments, a battery module including theventilation device is also provided.

Hereinafter, the disclosed technology will be described in detail withreference to embodiments and the accompanying drawings. However, thoseskilled in the art will appreciate that such embodiments described withreference to the accompanying drawings are provided to fully understandthe spirit of the disclosed technology and do not limit subject mattersto be protected as disclosed in the detailed description and appendedclaims.

The term “frame” used herein refers to an element of a ventilationdevice capable of controlling a direction of a gas generated in abattery cell in combination with a battery cell. A first frame and asecond frame are designated merely to be distinguished from each other,and positions or orders thereof are not specifically limited by theterms “first” and “second.”

FIG. 1 is a schematic perspective view illustrating a ventilation devicefor a pouch-type secondary battery in accordance with exemplaryembodiments.

In a ventilation device 100 for a pouch-type secondary battery of inFIG. 1 , refers to a length direction from a left side to a right side,or from the right side to the left side of the first frame and thesecond frame; “H” refers to a height direction upwardly or downwardly;“D” refers to a thickness direction from a front face to a rear face orfrom the rear face to the front face; and “h” refers to an intervalbetween the first frame and the second frame.

In FIG. 1 , an interval between the first frame and the second frame maybe a sufficiently close distance by which, e.g., a portion of a cellpouch may be in contact with the first frame and the second frame whenthe battery cell is inserted between the first frame and the secondframe.

Referring to FIG. 1 , a ventilation device 100 for a pouch-typesecondary battery (hereinafter, abbreviated as a ventilation device)according to an exemplary embodiment may include a first frame 110, asecond frame 120, and a connector 150 for connecting the first frame 110and the second frame 120 with each other. The first frame 110 and thesecond frame 120 may face each other.

The connector 150 may include a slit portion 151 extending between thefirst frame 110 and the second frame 120. In FIG. 1 , the connector 150and the slit portion 151 are indicated. with dotted lines inconsideration of the interval between the first frame 110 and the secondframe 120.

The “frame” used herein may refer to at least one of the first frame 110or the second frame 120.

The first frame 110 may include a first frame body 111, and the secondframe 120 may include a second frame body 121.

One surfaces of the first frame 110 and the second frame 120 may faceeach other. The first frame 110 may include a first frame facing surface112 facing the second frame 120, and the second frame 120 may include asecond frame facing surface 122 facing the first frame 110.

The first frame 110 and the second frame 120 may be fixed and connectedto each other by the connector 150. For example, the connector 150 mayextend from a rear surface of the first frame 110 to be connected to arear surface of the second frame 120.

The connector 150 may include, e.g., the slit portion 151. For example,the slit portion 151 may extend between the first frame 110 and thesecond frame 120 such that an electrode lead of the battery cell may beinserted through the slit portion 151 in a thickness direction of thefirst frame 110 and the second frame 120 when the battery cell isinserted into the ventilation device 100. A size or a length of the slitportion 151 may be appropriately adjusted within a range by which theelectrode lead of the battery cell may be inserted.

At least one of the first frame 110 and the second frame 120 may includea ventilation guiding portion 130 recessed at the facing surface.Further, a ventilation control portion 140 connected to the ventilationguiding portion 130 may be formed as a space formed between the firstframe 110 and the second frame 120. In the specific examples shown inFIGS. 1, 2A-2D, both the first and second frames 110 and 120 arestructured to include such a ventilation guiding portion 130. In otherimplementations, only one frame 110 or 120 may include a ventilationguiding portion 130.

For example, the first frame 110 may include the first frame facingsurface 112 facing the second frame 120 and a first ventilation guidingsurface 131 formed by being recessed from the first frame facing surface112. The second frame 120 may include the second frame facing surface122 facing the first frame 110 and a second ventilation guiding surface132 formed by being recessed from the second frame facing surface 122.The ventilation guiding portion 130 may be formed between the firstventilation guiding surface 131 and the second ventilation guidingsurface 132.

For example, the first ventilation guiding surface 131 recessed from thefirst frame facing surface 112 and the second ventilation guidingsurface 132 recessed from the second frame facing surface 122 may faceeach other to form a venting groove or a venting hole as the ventilationguiding portion 130.

A position at the frames 110 and 120 of the ventilation guiding portion130 or a shape of the ventilation guiding portion 130 may be properlyadjusted.

FIGS. 2A to 2D and FIGS. 3A to 3B are schematic perspective viewsillustrating ventilation devices for a pouch-type secondary battery inaccordance with some exemplary embodiments.

Detailed descriptions on elements or structures substantially the sameas or similar to those described with reference to FIG. 1 are omittedherein.

Referring to FIGS. 2A, the ventilation guiding portion 130 may be formedat an edge of the frames 110 and 120. For example, the ventilationguiding portion 130 may be adjacent to one end of the slit portion 150and may be opened to an outside of the frames 110 and 120.

Referring to FIGS. 2B to 2D, the ventilation guiding portion 130 may beformed at an inner region of the first frame 110 and the second frame120.

Referring to FIG. 3A, the ventilation guiding portion 130 may include aventing groove 135. For example, the venting groove 135 may include agroove formed at a front surface of the first frame 110. For example,the venting groove 135 may be recessed from the front surface of thefirst frame 110 and spaced apart from the rear surface of the firstframe 110.

Referring to FIG. 3B, the ventilation guiding portion 130 may include aventing hole 137. For example, the venting hole 137 may be a hole or anopening formed at the front surface of the first frame 110. For example,the venting hole 137 may be a hole extending from the front surface ofthe first frame 110 to the rear surface of the first frame 110.

The venting groove 135 or the venting hole 137 may serve as a passagethrough which a gas may be discharged to the outside, when the batterycell is inserted between the first frame 110 and the second frame 120and a ventilation occurs due to an increase of an internal pressure ofthe pouch during a battery operation.

In an embodiment, an inner shape of the venting hole 137 may include,e.g., at least one of a cylindrical shape, a semi-cylindrical shape, afunnel shape and a polygonal pillar shape.

As illustrated in FIGS. 2A to 2D, the inner shape of the venting hole137 may be the cylinder shape, the semi-cylindrical shape or the funnelshape.

For example, as illustrated in FIG. 2C, the venting hole 137 may havethe funnel shape. For example, the venting hole 137 may have the funnelshape in which a width becomes narrower from the front surface to therear surface of the frames 110 and 120. Alternatively, the venting hole137 may have the funnel shape in which the width becomes wider from thefront surface to the rear surface of the frames 110 and 120.

For example, the venting hole 137 may have a triangular pillar shape oran octagonal pillar shape.

In exemplary embodiments, a remainder space in which the pouch may beexpanded when the gas is generated in the pouch may be provided by theventilation guiding portion 130 serving as the venting groove or theventing hole. Thus, the gas may be induced to the ventilation guidingportion 130. Accordingly, the ventilation may be easily controlled orinduced without additional components or equipment.

In an embodiment, if the inner shape of the venting hole is any oneselected from the cylindrical shape, the semi-cylindrical shape and thefunnel shape, an average diameter may be from 1 mm Φ to 500 mm Φ,preferably from 5 mm Φ to 100 mm Φ. In the above range, the gasinduction and exhaustion to the ventilation guiding portion 130 may bepromoted.

FIG. 4 is a schematic perspective view illustrating a ventilation devicefor a pouch-type secondary battery in accordance with some exemplaryembodiments.

Referring to FIG. 4 , the venting guiding portion 130 may furtherinclude caps 115 and 125.

In this case, a portion of the battery cell pouch, e.g., a pouch sealingportion may be in contact with a first cap 115 and/or a second cap 125in the ventilation guiding portion 130. In exemplary embodiments, thecaps 115 and 125 may include a soft material that is more physicallydeformable than a material of the frames 110 and 120 is.

In an embodiment, when a pressure of a predetermined value of more isapplied to the caps 115 and 125 in the height, thickness or lengthdirection of the frames 110 and 120, the caps 115 and 125 may beseparated from the frame 110 and 120.

In an embodiment, when a heat of a predetermined value or more isapplied to the caps 115 and 125 in the height, thickness, or lengthdirection of the frame 110 and 120, the caps 115 and 125 may be melted.

In some embodiments, the caps 115 and 125 may include a low meltingpoint material. For example, the caps 115 and 125 may include tin (Sn),zinc (Zn), lead (Pb), bismuth (Bi), indium (In), etc. Accordingly, thecaps 115 and 125 may be transformed into a flowable state. Thus, a gasexhaust passage may be formed by the deformation of the caps 115 and125.

FIGS. 5A and 5B are schematic perspective views illustrating ventilationdevices for a pouch-type secondary battery in accordance with someexemplary embodiments.

Referring to FIGS. 5A and 5B, the slit portion 151 may include asub-venting hole 153 having substantially the same shape as that of theventilation guiding portion 130 at a position corresponding to theventilation guiding portion 130. Thus, an additional passage for anexternal discharge of gas when the ventilation occurs may be provided.

As illustrated in FIG. 5A, the ventilation guiding portion 130 may beformed at an inside of the frames 110 and 120, and the sub-venting hole153 may also be formed in the slit portion 151.

As illustrated in FIG. 5B, the ventilation guiding portion 130 may beformed at one end of the frames 110 and 120, and the sub-venting hole153 may also be formed at one end of the slit portion 151 to be openedto an outside of the connector 150.

As described above, the sub-venting hole 153 may be formed at a positioncorresponding to the ventilation guiding portion 130, and may have ashape corresponding to that of the ventilation guiding portion 130, sothat a structure more advantageous to a ventilation control may beprovided.

As shown in FIG. 1 , the connector 150 is shaped to connect the twoframes 110 and 120 to be separated from each other by a spacetherebetween as the ventilation control portion 140.

Accordingly, this construction allows the ventilation control portion140 to be provided as a space formed between the first frame 110 and thesecond frame 120, and to connect to the ventilation guiding portion 130.

For example, the ventilation control portion 140 may be formed betweenthe first frame 110 and the second frame 120 along the length directiondesignated as L of the frames 110 and 120, and may be connected to theventilation guiding portion 130. For example, when an electrode lead ofthe battery cell may be inserted into the slit portion 151 of theventilation device 100, a sealing portion of the pouch of the batterycell may be in contact with a surface of the frame 110 and 120 in theventilation control portion 140.

For convenience of illustration, in FIG. 1 , the interval between theframes 110 and 120 is illustrated as being relatively larger than anactual interval. However, the interval between the frames 110 and 120may be a sufficiently small so that the portion of the battery cell maycontact the surface of the frame when the battery cell is insertedbetween the frames 110 and 120.

Accordingly, when the gas is generated in the pouch, a space for anexpansion of the pouch may be reduced, so that the pouch expansion maybe suppressed. Accordingly, the generation of the ventilation may beinterrupted or delayed.

In some embodiments, the interval between the first frame 110 and thesecond frame 120 may be from 0.1 mm to 10 mm. The interval between thefirst frame 110 and the second frame 120 is designated as h in FIG. 1 ,and the interval h may be preferably from 2 mm to 5 mm. In the aboverange of the interval, the battery cell may be inserted and fixed in theventilation device 100 and the pouch expansion may be effectivelysuppressed during an operation of the battery cell.

In some embodiments, a length of each of the first frame 110 and thesecond frame 120 in the direction designated as F may be from 10 mm to500 mm, a height in the direction designated as H may be from 1 mm to 50mm, and a thickness in the direction designated as D may be from 1 mm to50 mm. Preferably, the length may be from 5 mm to 300 mm, the height maybe from 5 mm to 30 mm, and the thickness may be from 5 mm to 30 mm.

A size or a shape of the ventilation device may be property variouslymodified within a range in which the battery cell may be easily appliedto the ventilation device 100, and a ventilation direction may becontrolled by applying the battery cells to the ventilation device 100.

In an embodiment, the frames 110 and 120 may include a material havinghigh rigidity and high elasticity to withstand physical and chemicalforces applied from the outside. Further, the connector 150 may includethe same material as that of the frames 110 and 120.

In an embodiment, the frames 110 and 120 may include a material havinghigher rigidity or elasticity than a material included in the caps toprovide improved durability in harsh conditions. For example, the frames110 and 120 may include a plastic, a metal, a ceramic, or the like. Forexample, the plastic may include a widely used plastic, an engineeringplastic, etc. The metal may include aluminum, copper, iron, stainlesssteel, etc. The polymer may include a rubber, polyurethane foam, etc.

In some embodiments, the first frame 110, the second frame 120 and theconnector 150 may be integral with each other.

A pouch-type battery cell unit according to an exemplary embodiment maybe implemented by inserting the battery cell into the above-describedventilation device for a pouch-type secondary battery.

FIG. 6 is a schematic top plan view of a battery cell in accordance withexemplary embodiments.

Referring to FIG. 6 , a battery cell 200 may include an electrodeassembly 210 having an electrode lead 220 formed at one end thereof anda pouch 230 accommodating the electrode assembly 210.

The term “electrode lead 220” used herein may refer to at least one ofthe first electrode lead 221 and the second electrode lead 222.

The pouch 230 may include a sealing portion 240 formed at an outside ofthe electrode assembly 210.

The sealing portion 240 may include a side sealing portion 241 forsealing an end from which the electrode lead 220 is drawn out, and amain sealing portion 243 for sealing a side from which the electrodelead 220 is not drawn out. A folding portion 245 may be formed byfolding the pouch 230 at an edge of the main sealing portion 243.

The side sealing portion 241 may be a sealing portion located in adirection in which the electrode lead is drawn out of sealing portionsformed at the outside of the electrode assembly. The main sealingportion 243 may be a sealing portion connected to the side sealingportion 241 and located in a direction in which the electrode lead isnot drawn out. The folding portion 245 may refer to a structure in whichthe pouch extends at the edge of the main sealing portion 243 to befolded.

For example, an unnecessary space between adjacent battery cells may bereduced when assembling a battery module by forming the folding portion243. The folding portion 243 may be formed to be smaller than athickness of the electrode assembly and may not protrude. Thus, theadjacent battery cells may be disposed more closely to increase avolumetric efficiency of the battery module.

FIG. 7 is a schematic perspective view illustrating a battery cell unitin accordance with exemplary embodiments.

Referring to FIG. 7 , the battery cell 200 may be inserted into theventilation device 100. For example, the electrode lead 220 of thebattery cell 200 may be inserted into the slit portion 151 of theventilation device 100 from the front surface to the rear surface of theframes 110 and 120. In this case, portions of the electrode lead 220 andthe sealing portion 240 of the battery cell 200 may be located in theventilation control portion 140. For example, the side sealing portion241 may be located in the ventilation control portion 140 to be contactwith the first frame facing surface 112 and the second frame facingsurface 122.

The sealing portion 240 of the pouch may contact the frame facingsurfaces 112 and 122, so that expansion of the pouch may be suppressedby the frames 110 and 120 even when gas is generated in the pouch. Thus,the sealing portion 240 may be prevented from being disassembled due tothe gas expansion, thereby suppressing or delaying occurrence of thevent,

FIG. 8 is a schematic diagram for describing; an operation mechanism ofa battery cell unit in accordance with exemplary embodiments.

In a region (A) of FIG. 8 , the venting may be controlled by theventilation control portion 140. In a region (B) of FIG. 8 , the ventingmay be induced by the ventilation guiding portion 130.

When the pouch 230 of the battery cell 200 expands, the region (A) ofthe ventilation control portion 140 may directly contact the first frame110 and the second frame 120 to suppress an expansion of the sealingportion 240. Accordingly, a ventilation generation may be delayed orsuppressed, and a ventilation control may be implemented.

In the region (B) of the ventilation guiding portion 130, an expansionof the sealing portion 240 may be relatively allowed. Thus, the gasgenerated in the pouch 230 may be transferred to the region (B), and thepouch 230 may be expanded. Additionally, when an internal pressure ofthe pouch may become equal to or greater than an adhesive force of thesealing portion 240 by the gas generated in the pouch, the sealingportion 240 may be opened to cause an exhaustion of the gas to theoutside.

As described above, the gas generated in the pouch 230 may be exhaustedthrough the ventilation guiding portion 130. Accordingly, damages orexplosion of the battery cell may be prevented. Additionally, adirection of the gas exhaustion may be controlled by the ventilationguiding portion 130, so that a ventilation generation location may beeasily predicted.

As described above, even when an internal pressure of the secondarybattery is increased to an appropriate level or more, the venting may becontrolled to improve a durability to pressure. Accordingly, stabilityof the battery may be enhanced and deterioration of a batteryperformance may be prevented.

FIG. 9 is a schematic perspective view illustrating a battery module inaccordance with exemplary embodiments.

The battery module according to exemplary embodiments may include thebattery cell units applied to the ventilation device 100 as describedabove.

Referring to FIG. 9 , a battery module 400 may include a plurality ofthe battery cells 200. In an embodiment, the plurality of the batterycells 200 may be stacked by a surface contact with each other. Forexample, the plurality of the battery cells 200 stacked on each othermay form a battery stack, and the plurality of the battery cells 200 maybe electrically connected to each other by a bus bar assembly 300.

Each battery cell 200 may be a pouch-type battery in which the electrodeassembly 210 may be encapsulated by the pouch 230 as illustrated in FIG.6 . For example, the battery cell 200 may include the electrode assembly210 having an electrode lead 220 formed at one end thereof, and thepouch 230 accommodating the electrode assembly 210.

As described above, the pouch 230 may include the sealing portion 240formed at an outside of the electrode assembly 230.

As illustrated in FIG. 9 , the busbar assembly 300 may include a firstbusbar assembly 300 a disposed at one end of the battery stack, and asecond busbar assembly 300 b disposed at the other end of the batterystack. The first bus bar assembly 300 a and the second bus bar assembly300 b may face each other and may be spaced apart from each other withthe battery stack interposed therebetween.

In exemplary embodiments, the bus bar assembly 300 may include a mainframe 320, a bus bar 340 and an inner frame 360.

Referring to FIG. 9 , a battery module 400 may include a plurality ofthe battery cells 200. In an embodiment, the plurality of the batterycells 200 may be stacked by a surface contact with each other. Forexample, the plurality of the battery cells 200 stacked on each othermay form a battery stack, and the plurality of the battery cells 200 maybe electrically connected to each other by a bus bar assembly 300.

In the present specification, an outer surface of the main frame 320 mayrefer to an opposite side to a side at which the battery cells 200 aredisposed, and an inner surface may refer to the side at which thebattery cells 200 are disposed.

The main frame 320 may include a plurality of the slit portions 151 toaccommodate the electrode leads 220 of the battery cells 200. Theelectrode leads 220 extending from each battery cell 200 may be insertedand drawn out through each slit portion 151.

The bus bar 340 configured to electrically connect the electrode leads220 drawn out through the slit portions 151 may be mounted on the outersurface of the main frame 320.

A plurality of the inner frames 360 spaced apart from each other may becoupled to the inner surface of the main frame 320 to guide theelectrode lead 220 to the slit portion 151. spacing distance between theinner frames 360 may be from 0.1 mm to 10 mm.

FIGS. 10 and 11 are schematic cross-sectional views illustrating batterymodules in accordance with exemplary embodiments.

For example, FIG. 10 is a cross-sectional view of the battery module 400taken along a line B-B′ of FIG. 9 in a Y-axis direction. In a regionincluding a cut surface along the of the battery module 400, the innerframe 360 may include the ventilation guiding portion 130.

FIG. 11 is a cross-sectional view of the battery module 400 taken alonga line A-A′ of FIG. 9 in the Y-axis direction. In a region including acut surface of the line A-A′ of the battery module 400, the inner frame360 may include the ventilation control portion 140 (a space formedbetween the inner frames 360).

Referring to FIG. 10 together with FIG. 9 , a plurality of the innerframes 360 may be disposed by a predetermined interval along a direction(an X-axis direction) in which the plurality of the battery cells 200are stacked. The battery cell 200 may be interposed between the innerframes 360.

In an embodiment, the inner frames 360 and the battery cells 200 may bealternately and repeatedly arranged. At least one of the plurality ofthe inner frames 360 may include the ventilation guide portion 130 on asurface facing the adjacent inner frame 360.

As illustrated in FIG. 10 , at least one inner frame (a first innerframe) of the plurality of the inner frames 360 may have a first innerframe facing surface 361 facing the adjacent inner frame (a second innerframe). The first inner frame facing surface 361 may include a firstinner ventilation guide surface 362. The first inner ventilation guidesurface 362 may be formed by a portion of the first inner frame facingsurface 361 being recessed.

The second inner frame may include a second inner frame facing surface363 facing the first inner frame. The second inner frame facing surface363 may include a second inner ventilation guide surface 364. The secondinner ventilation guide surface 364 may be formed by a portion of thesecond inner frame facing surface 363 being recessed.

The ventilation guiding portion 130 may be formed between the firstinner ventilation guide surface 362 and the second inner ventilationguide surface 364.

In some embodiments, all of the plurality of the inner frames 360 mayinclude the ventilation guiding portion having a recessed shape at asurface facing the neighboring inner frame.

In some embodiments, the ventilation guiding portion 130 may be adjacentto one end of the slit portion 151, and may be opened to the outside ofthe inner frame 360.

According to some embodiments, an inner shape of the ventilation guidingportion 130 may be, e.g., a cylindrical shape, a semi-cylindrical shape,a funnel shape or a polygonal pillar shape.

The number, shape, size, and location of the ventilation guiding portion130 formed in the inner frame 360 may be appropriately modified within arange capable of controlling the ventilation generated in the batterycell 200.

The ventilation guiding portion 130 and the ventilation control portion140 may have substantially the same structure and shape as those of theventilation device 100 as described with reference to FIGS. 1 to 7 .

When the electrode lead 220 of the battery cell 200 is inserted into theslit portion 151 of the bus bar assembly 300, at least a portion of theelectrode lead 220 and the sealing portion 240 of the battery cell 200may be located in the ventilation control portion 140. For example, thesealing portion 240 may directly contact at least a portion of the innerframe facing surfaces 361 and 363 in the ventilation control portion140. For example, the side sealing portion 241 of the sealing portion240 may directly contact at least a portion of the inner frame facingsurfaces 361 and 363.

Referring to FIG. 11 , the side sealing portion 241 of the battery cell200 may contact at least a portion of the first and second inner framefacing surfaces 361 and 363 in the ventilation control portion 140,

For example, a contact area of the side sealing portion 241 with thefirst and second inner frame facing surfaces 361 and 363 may be from 200mm² to 20,000 mm², preferably 800 mm² to 20,000 mm².

In an embodiment, a contact area of the side sealing portion 241 withthe first inner frame facing surface 361 may be from 50 mm² to 5,000mm², and a contact area of the side sealing portion 241 with the secondinner frame facing surface 363 may be from 50 mm² to 5,000 mm². In theabove range, the occurrence of the ventilation may be more effectivelydelayed or suppressed.

For example, the side sealing portion 241 may contact the inner framefacing surfaces 361 and 361 in each of the first busbar assembly 300 aand the second busbar assembly 300 b disposed at one end and the otherend of the battery module 400, respectively.

As described with reference to FIG. 10 , in the ventilation guidingportion 130 formed in the inner frame 360, the inner frame facingsurfaces 361 and 363 and the side sealing portion 241 may not contacteach other, and thus a space for an expansion of the pouch 230 may beprovided when a gas is generated in the pouch 230 of the battery cell200. In an embodiment, when an internal pressure becomes equal to orgreater than an adhesive force of the sealing portion 240 by the gas atthe sealing portion 240 of the pouch 230, the sealing portion 240 may beopened and the gas may be exhausted to the outside.

In exemplary embodiments, the battery cell 200 may be a lithiumsecondary battery. The battery cell 200 may include the pouch 230 andthe electrode assembly 210 as described above. The electrode assembly210 may include repeatedly stacked electrodes and a separation layerdisposed between the electrodes. Each of the electrodes may include anactive material layer formed on an electrode current collector.

The electrodes may include an anode and a cathode. The electrode currentcollector may include a cathode current collector included in thecathode electrode and an anode current collector included in the anode.The active material layer may include a cathode active material layerincluded in the cathode and an anode active material layer included inthe anode.

The cathode may include the cathode current collector and the cathodeactive material layer formed by coating a cathode active material on thecathode current collector. The cathode active material may include acompound capable of reversibly intercalating and de-intercalatinglithium ions.

In some embodiments, the cathode active material may includelithium-transition metal composite oxide particles. Examples of alithium-transition metal composite oxide contained in thelithium-transition metal composite oxide particles may include alithium-manganese-based oxide, a lithium-cobalt-based oxide, alithium-nickel-based oxide, a lithium-manganese-cobalt-based oxide, etc.

In some embodiments, the lithium-transition metal composite oxideparticle may include nickel (Ni), and may further include at least oneof cobalt (Co) and manganese (Mn).

For example, the lithium-transition metal composite oxide particle maybe represented by Chemical Formula 1 below.

Li_(x)Ni_(1−y)M_(y)O_(2−z)X_(a)  [Chemical Formula 1]

In Chemical Formula 1, 0.9≤x≤1.1, 0≤y≤0.7, −0.1≤z≤0.1 and 0≤a≤0.1. M mayinclude at least one element selected from Na, Mg, Ca, Y, Ti, Zr, Hf, V,Nb, Ta, Ct, Mo, W, Mn, Co, Fe, Cu, Ag, Zn, B, Al, Ga, C, Si, Sn or Zr,and X may represent an element selected from O, F, S or P.

In some embodiments, a molar ratio (1−y) of nickel in Chemical Formula 1may be in a range from 0.8 to 0.95. In this case, power and capacity maybe increased through a high-nickel (High-Ni) cathode composition. As acontent of nickel included in the cathode active material increases,generation of a gas due to a side reaction between the cathode activematerial and an electrolyte may be increased. In exemplary embodiments,a ventilation of the gas may be efficiently controlled using theabove-described ventilation device 100.

In some embodiments, the lithium-transition metal composite oxideparticle may be represented by Chemical Formula 2 below, and may have anolivine structure.

LiMPO₄  [Chemical Formula 2]

In Chemical Formula 2, M may include at least one element selected fromFe, Mn, Ni, Co, and V.

The cathode current collector may include a metallic material that mayhave no reactivity in a charge/discharge voltage range of the lithiumsecondary battery and may be easily applied and adhered to the electrodeactive material. For example, the cathode current collector may include,e.g., stainless steel, nickel, aluminum, titanium, copper, zinc or analloy thereof, preferably aluminum or an aluminum alloy.

For example, a slurry may be prepared by mixing and stirring the cathodeactive material in a solvent with a binder, a conductive material and/ora dispersive agent. The slurry may be coated on the cathode currentcollector, and then dried and pressed to form the cathode including thecathode active material layer.

The binder may include an organic based binder such as a polyvinylidenefluoride-hexafluoropropylene copolymer (PVDF-co-HFP),polyvinylidenefluoride (PVDF), polyacrylonitrile,polymethylmethacrylate, etc., or an aqueous-based binder such asstyrene-butadiene rubber (SBR) that may be used with a thickener such ascarboxymethyl cellulose (CMC).

For example, a PVDF-based binder may be used as a cathode binder. Inthis case, an amount of the binder for forming the cathode activematerial layer may be reduced, and an amount of the cathode activematerial may be relatively increased. Thus, capacity and power of thelithium secondary battery may be further improved.

The conductive material may be added to facilitate electron mobilitybetween active material particles. For example, the conductive materialmay include a carbon-based material such as graphite, carbon black,graphene, carbon nanotube, etc., and/or a metal-based material such astin, tin oxide, titanium oxide, a perovskite material such as LaSrCoO₃or LaSrMnO₃, etc.

The anode may include the anode current collector and the anode activematerial layer formed by coating an anode active material on the anodecurrent collector.

The anode active material may include any widely known material capableof adsorbing and desorhing lithium ions. For example, a carbon-basedmaterial such as a crystalline carbon, an amorphous carbon, a carboncomposite material, a carbon fiber; a lithium alloy; a silicon(Si)-based active material or tin may be used.

The amorphous carbon may include a hard carbon, cokes, a mesocarbonmicrobead (MCMB), a mesophase pitch-based carbon fiber (MPCF), etc,

The crystalline carbon may include a graphite-based material such asnatural graphite, artificial graphite, graphitized cokes, graphitizedMCMB, graphitized MPCF, etc. The lithium alloy may further includealuminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium,indium, etc.

In an embodiment, the anode active material may include thesilicon-based active material to provide a high-capacity lithiumsecondary battery. The silicon-based active material may include SiOx(0<x<2) or a SiOx (0<x<2) containing a lithium compound. The SiOxcontaining the lithium compound may be a SiOx containing lithiumsilicate. Lithium silicate may be present in at least a portion of SiOx(0<x<2) particles. For example, lithium silicate may be present at aninside and/or on a surface of the SiOx (0<x<2) particles. In anembodiment, lithium silicate may include Li₂SiO₃, Li₂Si₂O₅, Li₄SiO₄,Li₄Si₃O₅, etc.

The silicon-based active material may also include, e.g., asilicon-carbon composite compound such as silicon carbide (SiC).

The anode current collector may include stainless steel, copper, nickel,aluminum, titanium, or an alloy thereof. Preferably, the anode currentcollector may include copper or a copper alloy.

For example, a slurry may be prepared by mixing and stirring the anodeactive material with a binder, a conductive material, a thickener, etc.,in a solvent. The slurry may be coated on the anode current collector,and then dried and pressed to form the anode including the anode activematerial layer.

The binder and the conductive material substantially the same as orsimilar to those used in the cathode active material layer may also beused in the anode. In some embodiments, the binder for forming the anodemay include, e.g., an aqueous binder such as styrene-butadiene rubber(SBR) for compatibility with the carbon-based active material, and maybe used together with a thickener such as carboxymethyl cellulose (CMC).

The separation layer may be interposed between the cathode and theanode. The separation layer may include a porous polymer film preparedfrom, e.g., a polyolefin-based polymer such as an ethylene homopolymer,a propylene homopolymer, an ethylene/butene copolymer, anethylenelhexene copolymer, an ethylenelmethacrylate copolymer, or thelike. The separation layer may also include a non-woven fabric formedfrom a glass fiber with a high melting point, a polyethyleneterephthalate fiber, or the like

In exemplary embodiments, an electrode cell may be defined by thecathode, the anode and the separation layer, and a plurality of theelectrode cells may be stacked to form the electrode assembly that mayhave e.g., a jelly roll shape. The electrode assembly may beaccommodated together with the electrolyte in the pouch to define thebattery cell (the lithium secondary battery).

In exemplary embodiments, a non-aqueous electrolyte may be used as theelectrolyte.

The non-aqueous electrolyte solution may include a lithium salt and anorganic solvent. The lithium salt may be represented by Li⁺X⁻. An anionof the lithium salt X⁻ may include, e.g., F⁻, Cl⁻, Br⁻, I⁻, NO₃ ⁻,N(CN)₂ ⁻, BF₄ ⁻, ClO₄ ⁻, PF₆ ⁻, (CF₃)₂PF₄ ⁻, (CF₃)₃PF₃ ⁻, (CF₃)₄PF₂ ⁻,(CF₃)₅PF⁻, (CF₃)₆P⁻, CF₃SO₃ ⁻, CF₃CF₂SO₃ ⁻, (CF₃SO₂ 2)₂N⁻, (FSO₂)₂N⁻,CF₃CF₂(CF₃)₂CO⁻, (CF₃SO₂)₂CH⁻, (SF₅)₃C⁻, (CF₃SO₂)₃C⁻, CF₃(CF₂)₇SO₃ ⁻,CF₃CO₂ ⁻, CH₃CO₂ ⁻, SCN⁻, (CF₃CF₂SO₂)₂N⁻, etc.

he organic solvent may include, e.g., propylene carbonate (PC), ethylenecarbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC),ethylmethyl carbonate (EMC), methylpropyl carbonate, dipropyl carbonate,dimethyl sulfoxide, acetonitrile, dimethoxy ethane, diethoxy ethane,vinylene carbonate, sulfolane, gamma-butyrolactone, propylene sulfite,tetrahydrofuran, etc. These may be used alone or in a combinationthereof.

The electrode current collector may include a notched portion. Thenotched portion may serve as, e.g., an electrode tab. The notchedportion may include a cathode notched portion protruding from thecathode current collector and an anode notched portion protruding fromthe anode current collector.

The electrode lead may be electrically connected to the notched portionand may be exposed to the outside of the pouch. The electrode lead mayserve as an external connection lead for applying power to the secondarybattery. Further, the electrode lead may include a cathode electrodelead and an anode lead.

A position of the ventilation device 100 may be properly modified inconsideration of a structure of the pouch-type secondary battery.

In some embodiments, the cathode lead and the anode lead may be disposedon both opposite sides of the secondary battery. In this case, theventilation device 100 may also be disposed at both sides of thesecondary battery.

In some embodiments, the cathode lead and the anode lead may be weldedtogether at one side of the pouch. In this case, the ventilation device100 may also be disposed at the one side of the secondary battery.

The foregoing is illustrative of example embodiments and is not to beconstrued as limitations to the disclosed technology. Although a fewexample embodiments have been described, various modifications to thedisclosed example embodiments and other embodiments claim may be madebased on what is disclosed in this patent document.

What is claimed is:
 1. A ventilation device for a secondary battery,comprising: a frame comprising a first frame and a second frame; and aconnector connecting the first frame and the second frame to each otherwith a space between the first and second frames as a ventilationcontrol portion, wherein the connector is structured to include a slitportion, wherein each of the first frame and the second frame includes afacing surface that faces each other, and at least one of the firstframe and the second frame includes a ventilation guiding portion thatis recessed from the facing surface and is connected to the ventilationcontrol portion.
 2. The ventilation device of claim 1, wherein: theconnector extends from a rear surface of the first frame to be connectedto a rear surface of the second frame; the first frame includes a firstframe facing surface facing the second frame and a first ventilationguiding surface recessed front the first frame facing surface; thesecond frame includes a second frame facing surface facing the firstframe and a second ventilation guiding surface recessed from the secondframe facing surface; and the ventilation guiding portion is formedbetween the first ventilation guiding surface and the second ventilationguiding surface.
 3. The ventilation device of claim 1, wherein: the slitportion extends between the first frame and the second frame; and theventilation guiding portion is adjacent to one end of the slit portionand is exposed to an outside of the frame.
 4. The ventilation device ofclaim 1, wherein the ventilation guiding portion comprises a ventinggroove.
 5. The ventilation device of claim 1, wherein the ventilationguiding portion comprises a venting hole.
 6. The ventilation device ofclaim 5, wherein an inner shape of the venting hole comprises at leastone of a cylindrical shape, a semi-cylindrical shape, a funnel shape anda polygonal pillar shape.
 7. The ventilation device of claim 6, whereinan average diameter of each of the cylindrical shape, thesemi-cylindrical shape and the funnel shape ranges from 1 mm Φ to 500 mmΦ.
 8. The ventilation device of claim 5, further comprising a cap fittedto the ventilation guiding portion.
 9. The ventilation device of claim8, wherein the cap comprises a material having a ductility greater thana ductility of a material of the frame.
 10. The ventilation device for apouch-type secondary battery of claim 1, wherein the slit portionincludes a sub-venting hole having the same shape as that of theventilation guiding portion at a position corresponding to theventilation guiding portion.
 11. The ventilation device of claim 1,wherein an interval between the first frame and the second frame rangesfrom 0.1 mm to 10 mm.
 12. A battery module, comprising: a plurality ofbattery cells stacked on each other, each of the plurality of batterycells comprising an electrode lead; and a bus bar assembly coupled to anend from which the electrode leads of the plurality of battery cells aredrawn out to connect the plurality of battery cells to each other,wherein the bus bar assembly comprises: a main frame comprising a slitportion from which the electrode leads of the plurality of battery cellsare drawn out; a bus bar mounted on an outer surface of the main frameto electrically connect the electrode leads drawn out through the slitportion to each other; and a plurality of inner frames spaced apart fromeach other on an inner surface of the main frame to guide the electrodeleads to the slit portion, wherein the plurality of inner framescomprises a first inner frame and a second inner frame neighboring eachother with a space therebetween as a ventilation control portion, andthe first inner frame comprises a ventilation guiding portion recessedfrom a surface facing the second inner frame and is connected to theventilation control portion.
 13. The battery module of claim 12,wherein: the first inner frame includes a first inner frame facingsurface facing the second inner frame, and a first inner ventilationguiding surface recessed from the first inner frame facing surface; thesecond inner frame includes a second inner frame facing surface facingthe first inner frame, and a second inner ventilation guiding surfacerecessed from the second inner frame facing surface; and. theventilation guiding portion is formed between the first innerventilation guiding surface and the second inner ventilation guidingsurface.
 14. The battery module of claim 13, wherein the plurality ofbattery cells each comprises an electrode assembly and a pouch foraccommodating the electrode assembly, wherein the pouch comprises asealing portion formed outside the electrode assembly, and wherein theelectrode lead and the sealing portion are at least partially located inthe ventilation control portion.
 15. The battery module of claim 14,wherein at least a portion of the sealing portion is in contact with atleast a portion of the first inner frame facing surface and the secondinner frame fa.cing surface in the ventilation control portion.
 16. Thebattery module of claim 15, wherein: the sealing portion comprises aside sealing portion sealing an end from which the electrode lead isdrawn out, and a main sealing portion sealing a side from which theelectrode lead is not drawn out; the main sealing portion includes afolding portion, wherein the pouch is folded at an edge of the foldingportion; and a contact area of the side sealing portion with the firstinner frame facing surface and the second inner frame facing surfaceranges from 200 mm² to 20,000 mm².
 17. The battery module of claim 12,wherein the ventilation guiding portion is adjacent to one end of theslit portion and is exposed to an outside of at least one of theplurality of inner frames.
 18. The battery module of claim 12, furthercomprising a cap fitted to the ventilation guiding portion.
 19. Thebattery module according to claim 12, wherein an interval between theplurality of inner frames ranges from 0.1 mm to 10 mm.
 20. The batterymodule of claim 12,wherein the slit portion includes a sub-venting holehaving the same shape as a shape of the ventilation guiding portion at aposition corresponding to the ventilation guiding portion.